.. _tan:

tan
===


Computes the element-wise tangent of vector elements.


.. contents::
    :local:
    :depth: 1

Description
***********

The ``tan(a)`` function computes tangent of vector elements.


Note that arguments ``abs(a[i]) ≤ 213`` and ``abs(a[i]) ≤ 216`` for
single and double precisions respectively are called fast
computational path. These are trigonometric function arguments for
which VM provides the best possible performance. Avoid arguments that
do not belong to the fast computational path in the VM High Accuracy
(HA) and Low Accuracy (LA) functions. Alternatively, you can use VM
Enhanced Performance (EP) functions that are fast on the entire
function domain. However, these functions provide less accuracy.

.. list-table::
   :header-rows: 1

   * -  Argument
     -  Result
     -  Error Code
   * -  +0
     -  +0
     -   
   * -  -0
     -  -0
     -   
   * -  +\ :math:`\infty`
     -  QNAN
     -  ``status::errdom``
   * -  -\ :math:`\infty`
     -  QNAN
     -  ``status::errdom``
   * -  QNAN
     -  QNAN
     -   
   * -  SNAN
     -  QNAN
     -   




Specifications for special values of the complex functions are defined according to the following formula:

``Tan(z) = -i*Tanh(i*z)``


API
***


Syntax
------

**Buffer API**


.. code-block:: cpp

   namespace oneapi::mkl::vm {

   sycl::event tan(sycl::queue & exec_queue,
         std::int64_t n,
         sycl::buffer<T> & a,
         sycl::buffer<T> & y,
         oneapi::mkl::vm::mode mode = oneapi::mkl::vm::mode::not_defined,
         oneapi::mkl::vm::error_handler<T> errhandler = {});

   }


.. code-block:: cpp

   namespace oneapi::mkl::vm {

   sycl::event tan(sycl::queue & exec_queue,
         sycl::buffer<T> & a,
         oneapi::mkl::slice sa,
         sycl::buffer<T> & y,
         oneapi::mkl::slice sy,
         oneapi::mkl::vm::mode mode = oneapi::mkl::vm::mode::not_defined,
         oneapi::mkl::vm::error_handler<T> errhandler = {});

   }


**USM API**

.. code-block:: cpp

   namespace oneapi::mkl::vm {

   sycl::event tan(sycl::queue & exec_queue,
         std::int64_t n,
         T const * a,
         T * y,
         std::vector<cl::sycl::event> const & depends = {},
         oneapi::mkl::vm::mode mode = oneapi::mkl::vm::mode::not_defined,
         oneapi::mkl::vm::error_handler<T> errhandler = {});

   }

.. code-block:: cpp

   namespace oneapi::mkl::vm {

   sycl::event tan(sycl::queue & exec_queue,
         T const * a,
         oneapi::mkl::slice sa,
         T * y,
         oneapi::mkl::slice sy,
         std::vector<cl::sycl::event> const & depends = {},
         oneapi::mkl::vm::mode mode = oneapi::mkl::vm::mode::not_defined,
         oneapi::mkl::vm::error_handler<T> errhandler = {});

   }


``tan`` supports the following precisions and devices:


.. list-table::
      :header-rows: 1

      * -  T
        -  Devices supported
      * -  ``float``
        -  Host, CPU, and GPU
      * -  ``double``
        -  Host, CPU, and GPU
      * -  ``std::complex<float>``
        -  Host
      * -  ``std::complex<double>``
        -  Host


Input Parameters
----------------

**Buffer API**


exec_queue
   The queue where the routine should be executed.


n
   Specifies the number of elements to be calculated.


a
   The buffer containing the input vector.


sa
   Slice selector for ``a``. See :ref:`data-types` for a description of the |O-MKL| slice type.


sy
   Slice selector for ``y``. See :ref:`data-types` for a description of the |O-MKL| slice type.


mode
   Overrides the global VM mode setting for this function call. See :ref:`set_mode` function for possible values and their description. This is an optional parameter. The default value is ``mode::not_defined``.


errhandler
   Sets local error handling mode for this function call. See the :ref:`create_error_handler` function for arguments and their descriptions. This is an optional parameter. The local error handler is disabled by default.


**USM API**


exec_queue
   The queue where the routine should be executed.


n
   Specifies the number of elements to be calculated.


a
   Pointer to the input vector.


sa
   Slice selector for ``a``. See :ref:`data-types` for a description of the |O-MKL| slice type.


sy
   Slice selector for ``y``. See :ref:`data-types` for a description of the |O-MKL| slice type.


depends
   Vector of dependent events (to wait for input data to be ready). This is an optional parameter. The default is an empty vector.


mode
   Overrides the global VM mode setting for this function call. See the :ref:`set_mode` function for possible values and their description. This is an optional parameter. The default value is ``mode::not_defined``.


errhandler
   Sets local error handling mode for this function call. See the :ref:`create_error_handler` function for arguments and their descriptions. This is an optional parameter. The local error handler is disabled by default.


Output Parameters
-----------------

**Buffer API**


y
   The buffer containing the output vector.


return value (event)
   Computation end event


**USM API**


y
   Pointer to the output vector.


return value (event)
   Computation end event


Examples
********

An example of how to use ``tan`` can be found in the |O-MKL|
installation directory, under:


.. code-block::


   examples/dpcpp/vml/source/vtan.cpp